Variation and evolution

Question 1

classification

Answer 1

placing objects into groups based of similar characteristics

Question 2

species

Answer 2

a group of individuals who can interbreed and produce fertile offspring

Question 3

variation

Answer 3

the differences between individuals of the same species

Question 4

what causes variation

Answer 4

sexual reproduction
meiosis
mutations

Question 5

inherited variation

Answer 5

differences between a species controlled by genes

Question 6

acquired variation

Answer 6

differences between a species that are learnt throughout an organisms life

Question 7

what is a mutation

Answer 7

a change in the structure or amount of DNA in an organism

Question 8

what may mutations produce

Answer 8

new alleles
beneficial phenotypes
no noticeable effect
genetic defects in offspring

Question 9

what are the 2 types of mutation?

Answer 9

gene mutation ie cystic fibrosis
chromosome mutation ie down syndrome

Question 10

mutagens

Answer 10

agents that change the DNA in a cell ie the chemicals in smoke, X-rays ect

Question 11

gene mutations

Answer 11

changes in a single gene that result in a protein being incorrectly made or not made at all

Question 12

Speciation

Answer 12

= production of a new species as a result of evolution

Question 13

Evidence of evolution

Answer 13

Fossils
. Fossils can be aged. These fossils are compared to modern organisms of the
same species and many differences are noticed.
* Modern fossils are more complex in structure
* Fossils can also help to indicate environmental changes
4 Fossils change structure overtime to reflect changes in the environment

Question 14

fossil

Answer 14

remains of organisms that lived a long time ago

Question 15

name 2 scientists associated with the theories of natural selection and evolution

Answer 15

Charles Darwin and Alfred Wallace

Question 16

Evolution

Answer 16

• is the changes between members of a species and the emergence of new species from older species over time, in response to change in the environment, due to natural selection.

Question 17

Natural selection -

Answer 17

is the mechanism by which members of a species, with genetic traits that allow them to survive in their environment, reproduce and pass these traits to the next generation.

Question 18

what were the 3 observations they based the theory of natural selection on

Answer 18

1Overbreeding - Many more offspring are produced than can possibly survive and reproduce.
2. Population remains constant - numbers of a species continue to grow until the environment can’t support any more.
3. Variation among a species arise from inherited differences (sexual reproduction, meiosis, mutations)

Question 19

what were the 2 conclusions they based their theory of natural selection on?

Answer 19

conclusion 1: there is a struggle for existence and some individuals have variations that make them better suited to survive than other individuals.

conclusion 2: Natural selection means organisms with variations that mare them better adapted to their environment will survive and reproduce

Question 20

describe the theory of natural selection

Answer 20

-over breeding results in competition
-individuals who best adapted survive, reproduce + pass down their traits to offspring
- a new species may eventually form